The present invention relates to a seal plate of a pressure container or a pressure adjusting mechanism for a seal plate. For example, the present invention relates to a seal plate or a pressure adjusting mechanism for a seal plate which is used in a battery (including a primary battery and a secondary battery) or a condenser (including an electrolytic condenser and an electric double layer condenser) or the like.
In conventional, a seal plate 51 shown in FIG. 12 has been known and is structured as follows.
That is, at first, there is provided a resin seal plate main body 52 for closing an opening portion 62 of a pressure container 61 for a secondary battery, an aluminum electrolytic condenser, an electric double layer condenser or the like, and a pair of metal terminals 53 and 53 are mounted to the seal plate main body 52. Further, there is provided an explosion preventing valve portion 54 having a breaking plate 55 breaking at a time when an internal pressure of the pressure container 61 reaches a predetermined value so as to release the internal pressure and preventing the pressure container 61 from exploding, in the seal plate main body 52.
However, the following disadvantages exist in the seal plate 51.
That is, at first, a rubber valve is attached to the explosion preventing valve portion 54 as an independent part, and the rubber valve breaks when the internal pressure in the sealed side abnormally increases, thereby functioning to stop an operation of the battery, the condenser or the like. However, since a material thereof is a rubber material, a dispersion of the breaking pressure is large and it is hard to control the breaking pressure.
Further, since a breather portion is not provided in the seal plate 51 mentioned above, it is necessary to previously keep a space for absorbing a temperature increase at a time when an electrolyte is reacted and an internal pressure increase due to a generated gas within the pressure container 61, so that there is a disadvantage that it is impossible to make the pressure container 61 compact.
The present invention is made by taking the points mentioned above into consideration, and an object of the present invention is to provide a seal plate in which a dispersion of a breaking pressure of a breaking plate can be reduced so that the breaking pressure can be easily controlled, and it is not necessary to provide a pressure absorbing space within a pressure container, whereby it is possible to make the pressure container compact, in comparison with the conventional art mentioned above.
Further, an object of the present invention is to provide a pressure adjusting mechanism for a seal plate which is not consumable at a time as the breaking plate in the explosion preventing valve mentioned above but can be continuously used after a pressure within the pressure container is released, does not require a pressure absorbing space provided within the pressure container, whereby it is possible to make the pressure container compact, and can serve with a stable operation characteristic.
Further, an object of the present invention is to provide a seal plate or a pressure adjusting mechanism for a seal plate which can prevent the pressure container from exploding due to an abnormal increase of a pressure within the pressure container even without having a rubber breaking plate with which it is hard to control the breaking pressure.
In order to achieve the object mentioned above, there is provided a seal plate characterized in that a breaking plate is integrally formed with a resin seal plate main body for closing an opening portion of a pressure container.
Further, there is provided a seal plate characterized by a breaking plate integrally formed with a resin seal plate main body for closing an opening portion of a pressure container, a thin portion integrally formed between the seal plate main body and the breaking plate and being thinner than the breaking plate, and an inclined surface portion formed to be gradually thicker from a thickness of the thin portion and provided in a peripheral edge portion of the breaking plate.
Further, there is provided a seal plate characterized in that a scattering prevention member such as a stop ring or the like for preventing the breaking plate from scattering to the outside of the seal plate when the breaking plate is broken is provided.
Further, there is provided a seal plate characterized in that a breather portion having a function membrane with gas permeability and liquid impermeability is provided.
Further, there is provided a pressure adjusting mechanism used in a pressure container such as a battery, an aluminum electrolytic condenser, an electric double layer condenser or the like, characterized by a function membrane releasing a pressure of the pressure container when the pressure becomes high and sucking a gas when the pressure becomes low, thereby keeping the inside of the pressure container at an atmospheric pressure, the function membrane being constituted by a porous body.
Further, there is provided a pressure adjusting mechanism characterized in that a water repellent treatment is applied to the function membrane so as to prevent a liquid from soaking into the function membrane constituted of a porous body.
Further, there is provided a pressure adjusting mechanism characterized in that a pressing member is provided so as to prevent the function membrane constituted of a porous body or a holding body thereof from being deformed to a certain level or more due to a pressure.
Further, there is provided a pressure adjusting mechanism characterized in that there is a function membrane structured such that a membrane-like porous body is formed by processing a PTFE material by a drawing method and a water repellent treatment is applied by coating fluoro chemicals.
Further, there is provided a pressure adjusting mechanism characterized in that a rubber-like elastic seal member for covering both sides in a direction of a membrane thickness and an outer peripheral side of a peripheral edge portion of the function membrane is assembled with the function membrane.
Further, there is provided a pressure adjusting mechanism characterized in that a rubber-like elastic seal member is assembled with both sides in a direction of a membrane thickness of the function membrane by an integral molding.
In the seal plate in accordance with the present invention provided with the structure mentioned above, since the breaking plate is integrally formed with the resin seal plate main body from the same kind of resin material, it is possible to make a dispersion of the breaking pressure smaller than the conventional one due to a material property of the resin material. Further, since the seal plate main body and the breaking plate are integrally formed instead of separated parts, it is possible to reduce the number of the parts.
Further, if the breaking plate is formed so as to have a uniform thickness at a time of integrally forming the breaking plate with the seal plate main body, there is a case that the breaking pressure can not be sufficiently controlled because the breaking plate is broken at an uncertain portion. With respect to this matter, as the seal plate in accordance with claim 2 of the present invention, it is effective to integrally form the thin portion thinner than the breaking plate between the seal plate main body and the breaking plate and provide the inclined surface portion being made gradually thicker from the thickness of the thin portion in the peripheral edge portion of the breaking plate. As mentioned above, when the thin portion being thinner than the breaking plate is integrally formed between the seal plate main body and the breaking plate and the inclined surface portion being made gradually thicker from the thickness of the thin portion is provided in the peripheral edge portion of the breaking plate, it is possible to concentrate the breaking portion in the thin portion, and thereby further easily control the breaking pressure.
In this case, in accordance with tests performed by the inventors of the present application, when an angle of incline of the inclined surface portion with respect to the breaking plate flat surface is set to 30 degrees or more, the angle of incline is particularly effective.
Further, an actual value of the breaking pressure can be selected in a design stage by suitably adjusting an inner diameter of the pressure releasing port (an outer diameter of the thin portion), an outer diameter of the breaking plate (an inner diameter of the thin portion), a thickness of the breaking plate, a thickness of the thin portion, an angle of incline of the inclined surface portion with respect to the breaking plate flat surface or the like.
Further, in addition, in the seal plate in accordance with the present invention provided with the structure mentioned above, it is possible to prevent the breaking plate from scattering to the outside of the seal plate when the breaking plate is broken. Further, in the seal plate it is possible to provide a breather function in the seal plate, and it is possible to provide a function for adjusting the pressure as well as for permeating the gas without permeating the liquid.
Further, the pressure adjusting mechanism is structured such as to be employed for the pressure container of the battery, the aluminum electrolytic condenser, the electric double layer condenser or the like in place of the explosion preventing valve in the prior art mentioned above. Since there is provided the function membrane releasing the pressure when the pressure within the pressure container becomes high and sucking the gas when the pressure within the pressure container becomes low so as to keep the inside of the pressure container in the atmospheric pressure, the function membrane being constituted by the porous body, it is possible to keep the pressure within the pressure container constant due to the gas permeable function or the breather function by the function membrane. Further, since there is no one-time consumable parts such as the breaking plate in the explosion preventing valve mentioned above, it is possible to continuously use the pressure adjusting mechanism after releasing the pressure within the pressure container. Further, since it is possible to set such as to optionally release the pressure without waiting that the pressure within the pressure container reaches a predetermined value, it is not necessary to provide the pressure absorbing space within the pressure container.
Further, in addition, in the pressure adjusting mechanism since the water repellent treatment is applied to the function membrane constituted of the porous body so as to prevent the liquid from soaking into the function membrane constituted of the porous body, it is possible to prevent the liquid such as the electrolyte or the like within the pressure container from permeating through the function membrane so as to leak to the outside.
Further, in the pressure adjusting mechanism since the pressing member is provided so as to prevent the function membrane constituted of the porous body or the holding body thereof from being deformed to a certain level or more due to the pressure, it is possible to prevent the function membrane or the holding body from being deformed and broken due to the high pressure within the pressure container or the like.
Further, in the pressure adjusting mechanism since the membrane-like porous body is formed by processing the PTFE material by the drawing method and the water repellent treatment is applied to the function membrane by coating the fluoro chemicals on the porous body, it is possible to constitute the function membrane excellent in a chemicals resistance by making the best use of the property that the PTFE is excellent in the chemicals resistance, and it is possible to effectively produce a lot of the function membranes by punching out from one drawn sheet.
Further, in the pressure adjusting mechanism since the rubber-like elastic seal member covering both sides in the direction of the membrane thickness and the outer peripheral side of the peripheral edge portion of the function membrane is assembled with the function membrane, it is possible to improve assembly efficiency and sealing performance.
Further, in the pressure adjusting mechanism since the rubber-like elastic seal member is assembled with both sides in the direction of the membrane thickness of the function membrane by the integral molding, it is also possible to improve assembly efficiency and sealing performance.